Separator for electric batteries



Dec. 30, 1924. 1,520,889

\ v. B. SEASE SEPARATOR FOR ELECTRIC BATTERIES Filed July 1920 15716428 offelfea or malledfiellulase nz'imzle fiber/'5 Fly 2 Fig 3 14B. Sease, INVENTOR BY ms ArTonwzYc fiAw-Al.

Patented Dec. 30, 1924.

UNITED STATES PATENT OFFICE.

VIRGIL B. SEASE, O'F PARLIN, NEW JERSEY, ASSIGNOR TO E. I. DU PONT DE NEMOUBS 8c COMPANY, OF WILMINGTON, DELAWARE, A CORPORATION OF DELAWARE.

SEPARATOR FOB ELECTRIC BATTERIES. I

Application filed July 8,

: new and useful Separators for Electric Batteries, of which the following is a specification.

This invention relates to'separators for electric batteries, and comprises as a new article of manufacture a separator consisting essentially of cellulose nitrate.

In testing the suitability of various porous materials for use as storage battery separators, I have discovered that cellulose,

nitrate has unique properties as a material for separators. Tests have shown that cellulose nitrate is far superior to wood or other forms of cellulose as regards resistance to the acid solution ordinarily used in storage batteries. Thus, nitrated cellulose has been observed to remain intact under conditions of temperature and strength of sulphuric acid that readily decomposed a sample of a standard wood separator such as generally used in batteries at the present. The cellulose nitrate used in forming the separator should preferably contain from 11 to 13% nitrogen. The new separator which constitutes my invention maybe made in various ways, but the following example illustrates one desirable embodiment of my invention.

Cellulose nit-rate fibers containing 11 to 13% nitrogen are pulped in a paper beater and formed into sheets or boards according to methods well known in the manufacture of paper. To reduce the fire risk the material is not dried completely on the rolls but finished with 10 to 15% moisture. The material is out into the desired size and strengthened at the corners or elsewhere b pieces of pyralin (a cellulose nitrate plasticl or other suitable material cemented or otherwise attached.

-A separator made of a cellulose nitrateboard in the above described manner has considerably greater durability than a standard wood separator.

Instead of a sheet or board of felted or' 1920. Serial No. 394,799.

other solvent and camphor or camphor substitute, and subjecting the colloided mass to the different operations, such as rolling, cake pressing, sheeting, and seasoning, which are well known in the manufacture of cellulose nitrate plastics. In order to form a separator from such a sheet of pyralin, I preferably sew a number of parallel rows of stitches through the sheet, using a 'nitrated cotton thread, which thread, in order to offer maximum resistance to the battery acid, should preferably contain from 11 to 13% nitrogen. T';.

The article made by sewing rows of stitches in a sheet of pyralin, and close equivalents of this article, may be referred to generically as a sheet of colloided cellulose nitrate, having perforations which are at least partly filled with. .threads or fibres of cellulose nitrate containing from 11 to 13% nitrogen.

Furthermore, in place of a separator composed entirely of cellulose nitrate, I may use any suitable material for the body of the separator, and provide, the surfaces thereof with a layer of cellulose nitrate so that the latter only comes in contact with the corrosive liquid of the battery. The separators constituting my invention are illustrated in the accompanying drawings inwhich Figure 1 is a side view of a separator, Figure 2 an end view of the separator shown in Figure 1, and Figure 3 a side view of a modified form of separator showing the rows of stitching.

Reference being had to Figure 1, the separator consists mainly of the sheet of felted or matted cellulose nitrate fibers 1, rei nforced at the corners with pieces 2 of a sheet of a cellulose nitrate plastic such as pyralin, these pieces being cemented to the sheet 1.

The modified separator shown in Figure 3 consists of a sheet 3 of colloided nitrocellulose (pyralin or celluloid) with parallel rows 4 of stitches, these stitches being made with a nitrated cotton thread.

l claim:

1. As a new article of manufacture an electric battery separator comprising a sheet or board made of cellulose nitrate contain- 5 ing from 11 to 13% of nitrogen, said sheet or board. being penetrable by water.

2. As a new article of manufacture an rsaoeee electric battery separator comprising a perforated sheet of colloideol cellulose nitrate, the perforations being at least partly filleol with threads or fibers of cellulose nitrate containing from 11 to 13% nitrogen.

In testimony whereof I aflix my signature.

VJllRGllL B. SEASE. 

